Macrophage accumulation in dorsal root ganglion is associated with neuropathic pain in experimental autoimmune neuritis.

Background: Neuropathic pain is a common symptom of Guillain-Barré syndrome (GBS). The infiltration of macrophages in the dorsal root ganglion (DRG) contributed to neuropathic pain in nerve injury. The underlying mechanisms of neuropathic pain in patients with GBS remain unknown. Experimental autoimmune neuritis (EAN) is a useful mice model of GBS. Our study aimed to explore whether the infiltration of macrophages in DRG is associated with neuropathic pain of EAN.

Methods: Male C57BL/6 mice were randomly divided into two groups, the EAN group ( = 12) and the control group ( = 12). Six mice in each group were sacrificed after anesthetization in the attack and remission phase, respectively. The 50% paw withdrawal threshold and clinical score were measured, and macrophages with its subtypes were detected in the spleen and DRG tissue.

Results: More macrophages infiltrated the DRG of the EAN group in the attack phase and mostly surrounded neurons in the DRG. The proportion of macrophages and pro-inflammatory macrophages in the spleen of mice with EAN was significantly higher than the control group in the attack phase.

Conclusion: The infiltration of macrophages in DRG might be associated with neuropathic pain of EAN and pro-inflammatory macrophages may involve in neuropathic pain of EAN.